(Updated March 25, 2020)
Table of standard headers files as defined by the many C standards that have been released.
<assert.h> Conditionally compiled macro that compares its argument to zero <complex.h> (since C99) Complex number arithmetic <ctype.h> Functions to determine the type contained in character data <errno.h> Macros reporting error conditions <fenv.h> (since C99) Floating-point environment <float.h> Limits of float types <inttypes.h> (since C99) Format conversion of integer types <iso646.h> (since C95) Alternative operator spellings <limits.h> Sizes of basic types <locale.h> Localization utilities <math.h> Common mathematics functions <setjmp.h> Nonlocal jumps <signal.h> Signal handling <stdalign.h> (since C11) Provides alignas and alignof convenience macros <stdarg.h> Variable arguments <stdatomic.h> (since C11) Atomic types <stdbool.h> (since C99) Boolean type <stddef.h> Common macro definitions <stdint.h> (since C99) Fixed-width integer types <stdio.h> Input/output <stdlib.h> General utilities: memory management, program utilities, string conversions, random numbers <stdnoreturn.h> (since C11) noreturn convenience macros <string.h> String handling <tgmath.h> (since C99) Type-generic math (macros wrapping math.h and complex.h) <threads.h> (since C11) Thread library <time.h> Time/date utilities <uchar.h> (since C11) UTF-16 and UTF-32 character utilities <wchar.h> (since C95) Extended multibyte and wide character utilities <wctype.h> (since C95) Functions to determine the type contained in wide character data